The present invention relates to an apparatus and a method for assembling an electric motor.
In the field of dynamoelectric machinery, and particularly electric motors, there is generally found in each the same basic components having a similar assembled working relationship among these components. Typically, electric motors include a stationary stator for operation of a rotor rotatably mounted on support structure, such that, a substantially true coaxially spaced relationship exist about the rotor within a core of the stator. To this end, the prior art discloses different kinds of motor structures assembled by methods especially developed to suit the structural requirements and needs of the particular motor.
A common structural approach in the prior art for accomplishing a true concentricity relationship between the rotor and the stator is to provide a motor support housing comprising separate sections with each section having openings, such as a bearing seat, for supporting ends of a rotor shaft. During assembly of the motor, the two openings must be precisely coaxially aligned for efficient motor performance and this is usually accomplished by a specially designed fixture. Once so aligned, a mechanical device, such as screws are used to permanently attach the orientated housing sections together. Motors built with individual housing sections having a rotor mount opening in each section are undesirable since they are complex and include a high part inventory. The sectional motor housing structures further demand excessive assembly time which often requires skilled adjustments. Consequently, such motors are difficult to economically produce in high volume.
In motor assembly techniques, epoxy resin is used as a bonding agent for attaching stationary motor components, especially within the stator. Epoxy resins and the like allows accurate assemblage of parts irrespective of dimensional variations as well as providing thermal, if desired, and electrical insulation. However, use of epoxy resin requires employment of elaborate assembly fixtures to accurately maintain and hold motor components during curing operation of the epoxy. These fixtures vary in structure for each different motor construction and usually include placement of shims to accurately gap the rotor and the stator during curing of the resin.
Examples of prior art assembly techniques are illustrated in U.S. Pat. Nos. 2,668,925, 3,256,590, 4,048,717 and 4,128,935.